Materials science communicationSynthesis of uniform-sized zeolite from windshield waste
Graphical abstract
Introduction
Every year worldwide scrapped vehicles make a significant contribution to the generation of waste. In recycled vehicle scrap, glass accounts for about 3% by weight. Many solutions have been suggested for recycling waste glass from scrapped vehicles, but a large amount of waste glass still goes to the landfill because of its high recycling cost [1], [2], [3]. In particular, the recycling of windshield waste creates a financial burden compared to other waste glass, due to the necessary separation of poly vinyl butyral (PVB) polymer safety film from the glass [4]. To encourage glass recycling, we must develop high-value recycling products to offset the recycling cost.
Many researchers have reported on eco-products that use recycled glass, such as eco-concrete, cement, bricks, and glass fibers [5], [6], [7], [8], [9]. Zeolite fabrication is also a possible alternative for recycling waste glass. Much industrial waste is used as source materials for zeolites, including coal fly ash, blast furnace slag, and waste LCD glass [10], [11], [12]. Windshield waste is highly suitable for the synthesis of zeolites because its main component is silicate but has not been used in eco-products yet.
Zeolites are microporous structures with three-dimensional cages and channels, made by connecting tetrahedral SiO4 and AlO4 units [13]. Zeolites take different forms such as sodalite, calcium aluminosilicate, limonite, zeolite X, and zeolite Y. A-type zeolite (Si/Al = 1) has exceptional capacity for ion-exchange, selective adsorption, and gas separation [14]. Synthetic zeolites are generally produced using a hydrothermal method in an alkaline medium at 200 °C [15]. Various types of zeolite can be synthesized in similar conditions. For producing high-purity A-type zeolite, many researchers suggest the optimization of synthesis variables such as heating rate, heating source, and acid treatment. Recently, M. Kamitani et al. reported the synthesis of A-type zeolite using environmentally friendly flat glass. They optimized acid-treatment and reaction time, but the synthetic zeolite still included impurities and unreacted glass powder. In order to use waste glass as a source material, its characteristics, such as particle size and size distribution, must be optimized to improve the properties of A-type zeolite [10], [11], [12], [16], [17].
Herein, we fabricate A-type zeolite from windshield waste via high-energy ball milling and a low-temperature hydrothermal method. Through high-energy ball milling, the windshield waste was reduced in average particle size for use as a source material for the synthesis of zeolite. Synthesis variables play an important role, but we confirm that the source material's conditions, such as particle size distribution, also affect the properties of synthetic A-type zeolite.
Section snippets
Experimental details
Windshield waste was provided in cullet form through the recycling process from the Seoul Glass Industry (Korea). Windshield cullet was ground using a mortar and pestle, and passed through a 270 mesh sieve. The micron-sized glass cullet was used as a source material for the synthesis of zeolite and is hereafter termed glass powder (GP). Sodium hydroxide (NaOH, 98+%, DAEJUNG, Korea) and sodium aluminate (NaAlO2, anhydrous, Sigma–Aldrich) were used without pretreatment.
A-type zeolite was prepared
Results and discussion
Fig. 1 displays pictures describing the change in windshield waste over the course of treatment. Windshield cullet particles of several millimeters in size (picture 1) became micro-scale GP (picture 2) by grinding and sieving at 270 mesh. GP was reduced in particle size by high-energy ball milling (picture 3). Then, FGP was treated with an aqueous solution of HNO3, removing impurities and unnecessary elements, to form a silicate-based material (picture 4). Finally, zeolite was fabricated
Conclusions
We successfully synthesized A-type zeolite from windshield waste via high-energy ball milling and a low-temperature hydrothermal process. Windshield waste was crushed to a fine glass powder by high-energy ball milling. As shown by SEM and PSA, the glass powder's average particle size of 3.2 μm was remarkably reduced to an average of 0.5 μm. Through XRF and EDS mapping, we demonstrated the effect of acid treatment: most elements other than silicon, such as Mg, Na, and Ca, were eliminated during
Acknowledgments
This study was supported by the R&D Center for Valuable Recycling(Global-Top Environmental Technology Development Program) funded by the Ministry of Environment (Project No.:2014001170002).
References (19)
- et al.
Recycling of waste glass as a partial replacement for fine aggregate in concrete
Waste Manage.
(2009) - et al.
Assessment of ecodesign potential in reaching new recycling targets
Resour. Conserv. Recycl.
(2010) - et al.
Glass-ceramics obtained by the recycling of end of life cathode ray tubes glasses
Waste Manage.
(2005) - et al.
A cost and benefit analysis of future end-of-life vehicle glazing recycling in France: a systematic approach
Resour. Conserv. Recycl.
(2013) - et al.
Development of glass-ceramics from boron containing waste and meat bone ash combinations with addition of waste glass
Ceram. Int.
(2014) - et al.
Recycling PC and TV waste glass in clay bricks and roof tiles
Waste Manage.
(2009) - et al.
Value-added utilisation of waste glass in concrete
Cem. Concr. Res.
(2004) - et al.
Synthesis and characterization of zeolite A from crushed particles of aluminoborosilicate glass used in LCD panels
J. Asian Ceram. Soc.
(2014) - et al.
Removal of Mn from aqueous solution using fly ash and its hydrothermal synthetic zeolite
J. Environ. Manage.
(2014)
Cited by (16)
Process engineering approach to conversion of alum sludge and waste glass into zeolite LTA for water softening
2021, Journal of Water Process EngineeringSynthesis of LTA zeolite beads using alum sludge and silica rich wastes
2021, Advanced Powder TechnologyCitation Excerpt :However, it was evident that achievement of a high yield, single-phase product was a remaining challenge. For example, Kim et al. [33] made zeolite LTA from windshield glass etched in 5 mol/L of HNO3 for 4 days at 70 °C to remove impurities such as potassium, calcium, magnesium and iron prior to zeolite crystallisation. Nevertheless, generation of large volumes of low pH liquid wastes constituted a major limitation of this study.
Zeolite synthesis from low-cost materials and environmental applications: A review
2020, Environmental AdvancesSynthesis of high value-added Na–P1 and Na-FAU zeolites using waste glass from fluorescent tubes and aluminum scraps
2020, Materials Chemistry and PhysicsFacile and affordable synthetic route of nano powder zeolite and its application in fast softening of water hardness
2020, Journal of Water Process EngineeringCitation Excerpt :This ratio is ranged from 1.06 to 1.27 and is close to the corresponding ratio to synthetic NaA zeolite. Additionally, the cubic shape and high crystallinity were confirmed from XRD results (Table 1) which are recognizable for NaA Zeolite [27,35,39,40]. Obtained results pointed to factors which have a great influence on the structure and morphology of the synthetic zeolite as precursors of used raw material and the temperature used herein in the preparation process.